using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace foryuki
{
    class Program
    {
        static void Main(string[] args)
        {
            int K = int.Parse(Console.ReadLine());
            int[] s = new int[] { 2, 3, 5, 7, 11, 13 };
            int[] g = new int[] { 4, 6, 8, 9, 10, 12 };
            int[] seki = new int[36];
            int index = 0;

            for (int i = 0; i < s.Length; i++)
            {
                for (int j = 0; j < g.Length; j++)
                {
                    seki[index] = s[i] * g[j];
                    index++;
                }
            }

            double ans = 0;
            var a = seki.Where(x => x == K).Select(x => seki);
            foreach (var item in a)
            {
                ans = a.Count();
            }
         
            Console.WriteLine(string.Format("{0:f16}", ans/36));
        }

        //-------------------------------------------------------------

        private int[] ConvertStringArrayToIntArray(string[] str, int defaultValue)
        {
            int[] b = Array.ConvertAll<string, int>(str, delegate(string value)
                {
                    return int.Parse(value);
                });

            for (int i = 0; i < b.Length; i++)
            {
                b[i] = defaultValue;
            }
            return b;
        }
    }
}